1. Field of the Invention
The present invention generally relates to a scanning type exposure apparatus and a device manufacturing method, wherein the exposure apparatus is preferably used in a lithography process for manufacturing micro-devices.
2. Description of the Related Art
In a lithography process for manufacturing micro-devices (e.g., semiconductors), two types of exposure apparatuses are known. One is a step-and-repeat type (so-called a stepper) and the other is a step-and-scan type (so-called a scanner or a scanning type exposure apparatus).
The former type uses a step-and-repeat sequence for transferring stepwise a pattern of an original (e.g., a reticle or a mask) onto a substrate (e.g., a semiconductor wafer or a glass or silicon substrate). In that sequence, the whole pattern of the original is illuminated and is projected onto one of a plurality of exposure regions on the substrate through a projection optical system, while the original and the substrate are maintained stationary. Next, the substrate is moved stepwise to change the exposure region, and then exposure is repeated in the same manner.
On the other hand, the latter type uses a step-and-scan sequence. In that sequence, an original pattern is illuminated with a slit-like beam and a portion of the pattern is projected onto one of a plurality of exposure regions on a substrate, while both the original and the substrate are scanningly moved. Next, the substrate is moved stepwise to change the exposure region, and then the exposure is repeated in the same manner.
The step-and-scan type exposure apparatus seems to have become the mainstream, at least for the near future, for the reason that it has a potential for high exposure performance in terms of an increase in transferring precision and field size.
The scanning type exposure apparatus includes stage devices (e.g., a wafer stage or a mask stage) for scanningly moving the wafer and the mask (reticle). While performing scanning exposure, the wafer stage and the mask stage are controlled synchronously by a master-slave control method. Generally, the wafer stage acts as the master stage and the mask stage as the slave stage, so that the mask stage follows the movement of the wafer stage in the scanning direction. The master-slave control method has an advantage of improving movement resolution, especially when the projection optical system is a reduced scale system.
In the conventional apparatus, however, there is a possibility of causing a relative deviation in all directions, except for the scanning direction, between the mask and the wafer. These directions include linear directions, i.e., the scanning direction (Y-direction) and directions (X-direction and Z-direction) perpendicular to the scanning direction, as well as rotational directions, each having X, Y, and Z rotational axes. In addition, the conventional apparatus does not have any mechanism to compensate for the deviation other than in the scanning direction. Therefore, it is difficult to increase pattern transferring accuracy of the scanning type exposure apparatus, and that makes it hard to manufacture a higher degree of integrated devices.
In view of above-described recognition about the prior art, a primary object of the present invention is to provide a scanning type exposure apparatus that is superior to the conventional apparatus.
In order to achieve the above object, the present invention, in a first aspect, provides a scanning type exposure apparatus including a substrate stage for holding a substrate and for moving the substrate in at least one of a scanning direction and a rotational direction, an original stage for holding an original and for moving the original in at least one of the scanning direction and the rotational direction, and a controller for controlling movements of the substrate stage and the original stage, wherein the controller synchronously controls the substrate stage and the original stage in the scanning direction, and independently controls the substrate stage and the original stage in the rotational direction.
Yet another object of the present invention is to provide an improved method for manufacturing micro-devices using the scanning type exposure apparatus.
In order to achieve the above object, the present invention, in another aspect, provides a device manufacturing method for manufacturing micro-devices, the method comprising holding a substrate with a substrate stage, moving the substrate, held on the substrate stage, in at least one of a scanning direction and a rotational direction, holding an original with an original stage, moving the original, held on the original stage, in at least one of the scanning direction, controlling, with a controller, movements of the substrate stage and the original stage, wherein the controller synchronously controls the substrate stage and the original stage in the scanning direction and independently controls the substrate stage and the original stage in the rotational direction, and transferring a pattern of the original onto the substrate, to manufacture microdevices.